dll serial fishing/patching help needed(easy)

[wassim_]

Hi guys.

I'm working on a program that can be licensed by three means:

Dongle
Flexlm (version 7.2)
a serial number

for obvious reasons, I'm trying to reverse the 3rd option (serial licensing).

What I've found is that the serial checking algo is in a dll that the main exe loads at runtime yet I can't break inside the dll using Bp GetDlgItem or Bp MessageBoxA in olly if I load the main exe and set breakpoints, so what should I do? where should I put my Bp to break on the serial checking algo?

Moreover, the Dll in question is not packed, yet a search referenced strings in olly doesn't show tha bad guy message so where could it be hiding? in intermodular calls?

Last question: An older version of this program stores the valid serial in a .ini file and checks it every time it runs, if I entered a fake serial in this ini, what kind of Bp should I use to break when the program loads this fake serial to check it out?

P.S: I'm using ollydebugger

Thank you in advance.